Macromonomers having reactive side groups

ABSTRACT

Rigid-rod macromonomers, and methods for preparing such macromonomers, having a polyaromatic backbone, solubilizing side groups, and reactive side groups are provided. The macromonomers are chemically incorporated into polymer systems to provide stronger, stiflened polymers.

CROSS-REFERENCE TO RELATED APPLICATION

This is a division of application Ser. No. 07/746,883, filed Aug. 19,1991.

FIELD OF THE INVENTION

This invention relates to soluble macromonomers having rigid-rodbackbones, pendant, flexible, solubilizing organic groups attached tothe backbone, and pendant reactive groups attached to the backbone ofthe macromonomer chains. They can be chemically incorporated into otherpolymer and monomer systems to yield strengthened, stiffened polymercompositions.

BACKGROUND OF THE INVENTION

It is well known that the stiffness and strength of a polymer arerelated to the flexibility of the polymer chain on the molecular level.Thus, if the chemical structure of the main chain restricts chaincoiling and flexing, the resulting polymer will be stiff and strong. Anexample of a stiff polymer is poly-1,4-phenylene-1,4-terephthalamide(PPTA). While PPTA can coil in solution, the amide linkages andpara-phenylene groups favor an extended chain Conformation. Fibers canbe prepared in which the chains are essentially all extended intorod-like conformations, and these fibers are extraordinarily strong andstiff. Unfortunately, PPTA is difficult to process (except for fiberspinning) and cannot be molded or extruded. In general, the more rigidthe polymer main chain the more difficult it is to prepare and process.

Some applications require strong, stiff materials that can be easilyprocessed by molding or extrusion. A widely used approach to obtain suchstiff materials is to add fillers such as carbon or silica, or toincorporate fibers, such as glass and carbon fibers, into a relativelyflexible polymer, thereby forming a stiff, strong composite material.The most widely utilized, high-performance fiber-polymer composites arecomposed of oriented carbon (graphite) fibers embedded in a suitablepolymer matrix.

The improvements in strength and stiffness of composites are related tothe aspect ratio of the filler or fiber, i.e., the length to diameterratio of the smallest diameter cylinder that will enclose the filler orfiber. To contribute reasonable strength and stiffness to the composite,the fibers must have an aspect ratio of at least about 25, andpreferably at least 100. Continuous fibers have the highest aspect ratioand yield the best mechanical properties but are costly to process. Lowaspect ratio materials, such as chopped fibers and fillers, give limitedimprovement in mechanical properties, but are easy and inexpensive toprocess. The success of composites is demonstrated by their wide use asstructural materials.

There are several drawbacks associated with composite materials.Composites are often more costly than the un-reinforced polymer. This isbecause of the expense of the fiber component and the additional laborneeded to prepare the composite. Composites are difficult or impossibleto repair and in general cannot be recycled. Many composites also haveundesirable failure characteristics, failing unpredictably andcatastrophically.

Molecular composites (composed of polymeric materials only) offer theprospect of high performance, lower cost and easier processability thanconventional fiber-polymer composites. In addition, molecular compositesgenerally can be recycled and repaired. Because molecular compositescontain no fibers, they can be fabricated much more easily thanfiber-polymer compositions, which contain macroscooic fibers.

Molecular composites are materials composed of a rigid-rod polymerembedded in a flexible polymer matrix. The rigid-rod polymer in amolecular composite can be thought of as the microscopic equivalent ofthe fiber in a fiber-polymer composite. The flexible polymer componentof a molecular composite serves to disperse the rigid-rod polymer,preventing bundling of the rigid-rod molecules. As in conventionalfiber/resin composites, the flexible polymer in a molecular compositehelps to distribute stress along the rigid-rod molecules via elasticdeformation of the flexible polymer. Thus, the second, or matrix-resinpolymer must be sufficiently flexible to effectively surround therigid-rod molecules while still being able to stretch upon stress. Theflexible and rigid-rod polymers can also interact strongly via Van derWaals, hydrogen bonding, or ionic interactions. The advantages ofmolecular composites over fiber-based composites are realized byincorporating rigid-rod segments into polymer systems. The advantages ofmolecular composites have been demonstrated by, e.g., W. F. Hwang, D. R.Wiff, C. L. Benner and T. E. Helminiak, Journal of MacromolecularScience. - Phys., B22, 231-257 (1983).

Molecular composites are simple mixtures or blends of a rigid-rodpolymer with a flexible polymer. As is known in the art, most polymersdo not mix with other polymers, and attempts at blends lead tomacroscopic phase separation. This is also true of rigid-rodpolymer/flexible polymer blends. Metastable blends may be prepared byrapid coagulation from solution. However, metastable blends will phaseseparate on heating, ruling out further thermal processing, such asmolding or melt spinning and use at high temperatures. The problem ofmacroscopic phase separation is reported in H. H. Chuah, T. Kyu, and T.E. Helminiak, Polymer, 28, 2130-2133 (1987). Macroscopic phaseseparation is a major limitation of molecular composites.

Rigid-rod polymers produced in the past are, in general, highlyinsoluble (except in the special case of polymers with basic groups,which may be dissolved in strong acids or in organic solvents with theaid of Lewis acids) and infusible. Preparation and processing of suchpolymers is, accordingly, difficult. A notable exception is found inU.S. patent application Ser. No. 07/397,732, filed Aug. 23, 1989(assigned to the assignee of the present invention), now U.S. Pat. No.5,227,457, which is incorporated herein by this reference. The rigid-rodpolymers described in the above-referenced application have a rigid-rodbackbone comprising a chain length of at least 25 organic monomer unitsjoined together by covalent bonds wherein at least about 95% of thebonds are substantially parallel; and solubilizing organic groupsattached to at least 1% of the monomer units. The polymers are preparedin a solvent system that is a solvent for both the monomer startingmaterials and the rigid-rod polymer product. The preferred monomer unitsinclude: paraphenyl, parabiphenyl, paraterphenyl, 2,6-quinoline,2,6-quinazoline, paraphenylene-2-benzobisthiazole,paraphenylene-2-benzobisoxazole, paraphenylene-2-benzobisimidazole,paraphenylene-1-pyromellitimide, 2,6-naphthylene, 1,4-naphthylene,1,5-naphthylene, 1,4-anthracenyl, 1,10-anthracenyl, 1,5-anthracenyl,2,6-anthracenyl, 9,10-anthracenyl, and 2,5-pyridinyl.

The rigid-rod polymers described above can be used as self-reinforcedengineering plastics and exhibit physical properties andcost-effectiveness superior to that exhibited by many conventionalfiber-containing composites. It would be quite useful if rigid-rodpolymers could be incorporated into conventional flexible polymers,especially large volume commodity polymers. The value of a flexiblepolymer would be increased significantly if its mechanical propertiescould be enhanced by addition of rigid-rod polymers. Such molecularcomposites could displace more expensive engineering resins andspecialty polymers and conventional composites as well. To date,practical molecular composites have not been demonstrated. This ischiefly due to deficiencies in currently available rigid-rod polymers,namely, limited solubility and fusibility and unfavorable chemical andphysical interactions between the rigid-rod and the flexible polymercomponent.

There is a need in the art for a rigid-rod polymer that can bechemically incorporated into flexible polymers and polymer systems,during or subsequent to polymerization, to thereby add strength and/orstiffness to the resulting polymers. Chemical rather than physicalincorporation is desirable to inhibit phase separation during theprocessing and use of the polymer and to increase the resultingpolymer's solvent resistance. The mechanical behavior of polymer systemswhich contain chemically incorporated rigid-rod moieties can bedifferent and superior to physical blends of, for example, rigid-rodpolymers with flexible polymers.

SUMMARY OF THE INVENTION

It has now been found that, for any given polymer, improvements instiffness and strength can be obtained by preparing a copolymer,thermoset resin, or the like, which incorporates rigid segments and themore flexible segments of the original polymer. These rigid segments actin a manner conceptually similar to the way stiff fibers act toreinforce composites; however, in the present invention no macroscopicfibers are present.

In the present invention, the problem of macroscopic phase separation,found in molecular composites, is avoided by the use of rigid-rodmacromonomers having reactive side groups. In one embodiment of thepresent invention, the rigid-rod macromonomers are made to react withflexible polymers, via reactive side groups, to form covalent bondsbetween the rigid-rod macromonomer and the flexible polymer, therebypreventing macroscopic phase separation.

In a second embodiment, macroscopic phase separation is prevented byforming the flexible polymer in the presence of the macromonomer. Thereactive side groups of the macromonomer react with monomers duringpolymerization of the flexible polymer, forming covalent bonds betweenthe macromonomer and flexible polymer.

In a third embodiment, the rigid-rod macromonomer is modified, by way ofchemical transformation of its reactive side groups, such that the sidegroups are made compatible with the flexible polymers. Compatibilizersinclude groups which will interact with the flexible polymer ionically,by hydrogen bonding, or by van der Waals interactions. Compatibilizersmay be polymeric or oligomeric. For example, a rigid-rod macromonomermay be made to react, via its reactive side groups, with caprolactam toform short polycaprolactam chains at various locations along themacromonomer chain, the resulting polycaprolactam-modified macromonomerbeing compatible with polycaprolactam.

It should be understood that while macroscopic phase separation isprevented, there may be varying degrees of microscopic phase separation.Microscopic phase separation results in the formation of phases thathave sizes on the order of the dimensions of the polymer chain.Microphase separation may be conducive to significant improvementsin.mechanical or other properties desired from incorporation ofrigid-rod macromonomers.

In a fourth embodiment, the rigid-rod macromonomers are used alone asthermosetting resins. In this case, the side groups provide some degreeof processability and will react under the appropriate conditions (e.g.heat, irradiation, exposure to air, etc.) to form crosslinks and effectcuring.

In a fifth embodiment, the rigid-rod macromonomers are used to modifyceramics and inorganic glasses, using sol-gel or other methods known inthe art. Here, the reactive side groups undergo special interactionswith the inorganic matrix, either polar, ionic or covalent.

Other methods of incorporating the rigid-rod macromonomers of thepresent invention into materials are contemplated and depend on thechemistry and properties of the material to be modified.

In one embodiment of the invention, the macromonomers have the structure(1): ##STR1## where each G₁, G₂, G₃, and G₄, on each monomer unit,independently, is either hydrogen, a solubilizing side group, or afunctional ("reactive") side group, and the number average degree ofpolymerization, DP_(n) , is greater than about 6. If DP_(n) is less thanabout 7 or 8, the rigidity and stiffness of polymers incorporating suchmacromonomers are only slightly increased. Preferably, DP_(n) is between10 and 500. In some applications, however, macromonomers prepared inaccordance with the present invention having a DP_(n) as low as 4 may beuseful, for example, as a means of decreasing the thermal expansioncoefficient of a flexible polymer, such as a polyimide or a polyamide.

At least one monomer unit in the macromonomer has at least one reactiveside group or reactive solubilizing side group. A description of suchgroups is provided below.

The structures presented here show only a single monomer unit and do notimply regular head-to-tail arrangement of monomer units along the chain.Monomer units may have random orientation or may be alternatinghead-to-head, tail-to-tail, or regular head-to-tail, or have otherarrangements, depending on the conditions of the polymerization andreactivity of monomers.

The macromonomers of the present invention may also contain heteroatomsin the main chain. Heteroaromatic rigid-rod macromonomers have structure(2), where A₁, A₂, A₃, and A₄ on each monomer unit, independently, maybe carbon or nitrogen, and each G is as defined above, except that wherean A is nitrogen, the corresponding G is nil. ##STR2##

As with structure (1), the macromonomers cf structure (2) have at leastone monomer unit that has at least one reactive side group or reactivesolubilizing side group.

Other rigid-rod monomer units can also be incorporated into themacromonomers prepared in accordance with the present invention. Thus arigid-rod macromonomer having monomer units of the type shown instructures (1) and/or (2) and benzobisthiazole monomer units ##STR3##can be used in the same way as (1) and (2). Likewise, rigid-rodpyromellitimide, benzobisoxazole, benzobisimidazole and other rigid-rodmonomer units may be substituted for some of the phenylene units withoutloss of function. The benzobisimidazole, thiazole and oxazole units mayhave either a cis or trans configuration.

The rigid-rod macromonomers of the present invention may be furtherpolymerized or cured by virtue of their reactive side groups. Dependingon the nature of the side groups and cure conditions, branched, network,or other structures result.

The macromonomers of the present invention may be used to formthermosets, either alone or in combination with other thermosettingpolymers. The macromonomers may also be used with thermoplastics, e.g.,by forming a copolymer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of the formation of a crosslinkedpolymer prepared by reacting macromonomers of the present invention withone species of complementary monomers;

FIG. 2 is a schematic illustration of the formation of a crosslinkedpolymer prepared by polymerizing macromonomers of the present inventionwith two different species of complementary monomers;

FIG. 3 is a schematic illustration of the formation of a graft polymerformed with macromonomers of the present invention;

FIG. 4 is a schematic illustration of the formation of asemi-interpenetrating network of an uncrosslinked flexible polymer in anetwork of a crosslinked monomer/macromonomer system;

FIG. 5 is a schematic illustration of the formation of a graft copolymerformed with macromonomers of the present invention wherein the reactiveside groups are polymerization initiators; and

FIG. 6 is a schematic illustration of the formation of a crosslinkedpolymeric material made with macromonomers of the present inventionwherein the reactive side groups can participate in addition typepolymerization.

DETAILED DESCRIPTION OF THE INVENTION

As discussed above, the strength and stiffness of a polymer are relatedto the flexibility of the polymer chain on a molecular level. It has nowbeen found that for any given polymer, improvements in stiffness andstrength can be obtained by preparing a copolymer having rigid segmentsas well as the more flexible segments of the original polymer. Theserigid segments act in a manner conceptually similar to the way stifffibers act to reinforce composites, however, in the present invention nomacroscopic fibers are present. The rigid segments are provided byincorporating rigid-rod macromonomers having structures (1) and/or (2)during or subsequent to polymerization of the flexible polymer. Severalapproaches are provided by the present invention.

Macromonomers having structure (1) are solubilized polyparaphenyleneshaving reactive functional side groups. Macromonomers having structure(2) are aza derivatives of polyparaphenylenes having reactive sidegroups. In each case, G₁ through G₄ are solubilizing side groups,functional side groups, or hydrogen, and the number average degree ofpolymerization, DP_(n), is greater than about 6, preferably between 10and 500.

The terms "reactive side group," "functional side group," and the likeare defined to mean any chemical moiety attached to the backbone of arigid-rod macromonomer molecule, which chemical moiety can be used in asubsequent reaction to effect one or more of the following reactions:

a) Reaction with a flexible polymer resulting in formation of one ormore covalent bonds between the macromonomer and the flexible polymer;

b) Reaction with monomers, either before or during a reaction in whichsuch monomers are polymerized to give a flexible polymer, resulting information of one or more covalent bonds between the macromonomer and theresulting flexible polymer;

c) Reaction with an oligomer or other small molecular species, resultingin increased compatibility of the rigid-rod macromonomer with flexiblepolymers in blends, mixtures, composites, copolymers, composites, alloysand the like; and

d) Polar, ionic, or covalent interaction with an inorganic matrix,resulting in a modified ceramic or an inorganic glass or glass-likematerial.

Reactive groups may be transformed by further chemical reaction,including without limitation, oxidation, reduction, deprotonation,halogenation, Schiff base formation, hydrolysis, electrophilic ornucleophilic substitution, and the like, to yield new reactive groups.

One skilled in the art will recognize that it sometimes will bedesirable to incorporate such reactive side groups in a protected formin order to ensure that the reactive group does not poison or otherwiseparticipate in or interfere with the macromonomer-forming reaction,e.g., an amine can be incorporated as an amide, a carboxylic acid can beincorporated as an ester, and an alcohol can be incorporated as an esteror as an ether. Once formation of the macromonomer has been completedthe protected reactive side group can then be deprotected, e.g., anamide or an ester can be hydrolyzed to produce an amine and an alcohol,respectively.

Non-limiting examples of reactive side groups include acetals, acetalsfrom ethylvinylether, acetylenes, acetyls, acid anhydrides, acids,acrylamides, acrylates, alcohols, aldehydes, alkanols, alkyl aldehydes,alkyl ketones, amides, amines, alkyl halides, anilines, aryl aldehydes,aryl ketones, azides, benzocyclobutenes, biphenylenes, carbonates,carboxylates, carboxylic acids and their salts, carboxylic acid halides,carboxylic anhydrides, cyanates, cyanides, epoxides, esters, ethers,formyls, fulvenes, halides, heteroaryls, hydrazines, hydroxylamines,imides, imines, isocyanates, ketals, ketoalkyls, ketoaryls, ketones,maleimides, nadimides, nitriles, olefins, phenols, phosphates,phosphonates, quaternary amines, silanes, silicates, silicones, silylethers, styrenes, sulfonamides, sulfones, sulfonic acids and theirsalts, sulfonyl halides, sulfoxides, tetrahydropyranyl ethers,thioethers, urethanes, vinyl ethers, vinyls and the like. In some cases,the functional side groups are capable of reacting with each other.Reactive side groups may be oligomeric or polymeric. Reactive sidegroups may also be bridging groups, such as --CH₂ CH═CHCH₂ --.

One skilled in the art will recognize that reactive groups can beprepared from "non-reactive" groups and "less reactive" groups. Forexample, some applications make it desirable to incorporate a rigid-rodpolymer having tolyl end groups into a flexible polyester. The tolylgroup is unreactive toward polyesters or polyester monomers, however,the tolyl group can be oxidized to a reactive carboxyphenyl group whichthen can react with polyesters by trans-esterification or with polyestermonomers to form polyesters containing the rigid-rod macromonomer.Similarly, a relatively non-reactive acetyl group can be modified byformation of a Schiff's base with 4-aminophenol, to give a macromonomerhaving phenolic end groups, useful for reinforcing thermoset resins suchas epoxies and phenolics. Other examples will be apparent to thoseskilled in the art.

The term "solubilizing side group" as used herein means a chemicalmoiety which, when attached to the backbone of the macromonomer,improves the solubility of the macromonomer in an appropriate solventsystem. For the purposes of the present invention, the term "soluble"will mean that a solution can be prepared containing greater than 0.5%by weight of the macromonomer or greater than about 0.5% of themonomer(s) being used to form the macromonomer.

One skilled in the art will appreciate that various factors must beconsidered in choosing a solubilizing group for a particular polymer andsolvent, and that, all else being the same, a larger or higher molecularweight solubilizing group will induce a higher degree of solubility.Conversely, for smaller solubilizing groups, matching the properties ofthe solvent and solubilizing groups is more critical, and it may benecessary to have, in addition, other favorable interactions inherent inthe structure of the polymer to aid in solubilization.

For the macromonomers of the present invention any given non-hydrogenside group G can act as a solubilizing group, a reactive group, or botha solubilizing and reactive group; the latter being referred to as areactive solubilizing group.

The number average degree of polymerization, DP_(n), is defined by:

DP_(n) =(number of monomer molecules present initially)/(number ofpolymer or oligomer chains in the system).

The number average molecular weight, M_(n) is defined by:

M_(n) =M_(o) ×DP_(n)

where M_(o) is the weight of one monomer unit in the chain.

The number average degree of polymerization DP_(n) is indicated instructural formulae, as in structure (1), by "n".

Compounds having structure (1) or (2) are solubilized rigid-rodmacromonomers having reactive side groups. Such macromonomers are rigidor stiff on both the microscopic and macroscopic level. Thesemacromonomers can be incorporated into other polymers via the sidegroups G which are reactive side groups and will impart stiffness andstrength to the resultant polymers. The distinction between oligomersand polymers is that the properties of an oligomer change measurably onchanging the degree of polymerization by one, while for a polymer addingan additional monomer unit has little effect on properties. Since therange of DP_(n) (>6) considered here covers both oligomers and polymers,and since this technical distinction is not of great importance to theapplications of these compounds, we will use the term macromonomer toimply the entire range from oligomers to polymers.

In macromonomers having structure (2), if only one of the A's isnitrogen, for example if A₄ is N, substituted polypyridines of structure(3) result: ##STR4##

If only A₁ and A₂ are N, the monomer unit is a pyridazine; if only A₁and A₃ are N, the monomer unit is a pyrazine, if only A₁ and A₄ are N,the monomer unit is a pyrimidine. If three A's are N, the monomer unitis a triazine. other heterocyclic monomer units are included if some ofthe G's are bridging, for example, if G₁ and G₂ are --CHCHCHCH--, and A₃is N, the monomer unit is an isoquinoline.

Macromonomers having the structure (2) include compounds of thestructure (1) as a subset.

It is possible to have rigid-rod macromonomers in accordance with thepresent invention comprising several types of monomer units, each with adifferent set of A's and G's, i.e., each A₁, A₂, A₃ and A₄ on eachmonomer unit, independently is C or N, and each G₁, G₂, G₃, and G₄ oneach monomer unit, independently is H, a solubilizing side group, or areactive side group. In other words, adjacent monomer units need not beidentical. Macromonomers comprised of different monomers arecopolymer-type macromonomers.

As stated above, the number and type of side groups necessary to impartsolubility will depend on n and the nature and number of reactive sidegroups. If n is small, only a few side chains will be needed forsolubility. That is, only some of the monomer units in each chain may besubstituted; the rest are either unsubstituted, i.e., the G's are all H,or are non-solubilizing reactive side groups. Where n is very small andthe reactive side groups aid solubility, few "solubilizing" side groupsare required. Where n is large, solubility may be maintained by usingmore non-H G's per chain or by using G's with higher molecular weight.In many cases, the macromonomer will have exactly one non-hydrogen G permonomer unit, i.e. G₁ =solubilizing and/or reactive side group, and G₂═G₃ ═G₄ ═H. Structures (1) and (2) are meant to imply both homopolymersand copolymers where not all monomer units have the same set of G's.

Depending on relative reactivity of the reactive side groups, the numberof reactive side groups, the concentrations of flexible polymer ormonomer and macromonomer, and the like, various structures of rigid-rodreinforced polymeric composition will be obtained. At one extreme, therigid rod macromonomer will form one or more bonds at each monomer unit,so that many reactive groups per rigid rod chain are used, and manycrosslinks are made between the rigid rod macromonomer and flexiblepolymer. Such highly crosslinked structures will be most useful asthermosets and should be processed accordingly (the majority of thecrosslinks should be made after the material has been shaped or formed;i.e., macromonomers and flexible monomers are reacted in a mold orapplied as a coating and then cured; macromonomers, flexible polymersand a catalyst are mixed, shaped and cured; etc.)

At the other extreme, only a few reactive side groups per macromonomerchain are available to form crosslinks, and a thermoplastic structureresembling a graft copolymer results. In one embodiment, each rigid-rodchain has many reactive side groups, but their reactivity is low under apredetermined set of conditions, and only some of the reactive groupsparticipate in crosslinking, the rest remain unreacted. In anotherembodiment, in addition to macromonomers and a flexible polymer, a thirdcomponent is added, which third component will cap some of the reactivegroups, rendering them inert. This approach is useful for tailoring onetype of macromonomer for different applications requiring differentdegrees of crosslinking. In another embodiment, each macromonomer chainhas only a few reactive side groups, the rest being inert underprocessing conditions.

It will be recognized by one skilled in the art that a particular sidegroup may be inert in one circumstance and reactive in another. Forexample, an amide side group may be reactive under conditions oftransamidation, and able to form covalent bonds with flexiblepolyamides, but inert toward non-amide polymers such as polystyrene orpolyvinylchloride.

The macromonomers of the present invention may interact differently withdifferent classes of flexible polymers, for example, addition polymersand condensation polymers. A non-limiting list of flexible polymers thatcan incorporate the macromonomers of the present invention includespolyacetals, polyamides, polyimides, polyesters, polycarbonates,polyamide-imides, polyamide-esters, polyamide ethers,polycarbonate-esters, polyamide-ethers, polyacrylates; elastomers suchas polybutadiene, copolymers of butadiene with one or more othermonomers, butadiene-acrylonitrile rubber, styrene-butadiene rubber,polyisoprene, copolymers of isoprene with one or more other monomers,polyphosphazenes, natural rubber, blends of natural and syntheticrubber, polydimethylsiloxane, copolymers containing the dimethylsiloxaneunit, polydiphenylsiloxane, copolymers containing the diphenylsiloxaneunit; polyalkylmethacrylates, polyethylene, polypropylene, polyphenyleneoxide, polyphenylene sulfide, polystyrene, polyvinylacetate,polyvinylalcohol, and polyvinylchloride.

REINFORCING CONDENSATION POLYMERS

Rigid segments may be introduced into a wide variety of condensationpolymers through the use of the rigid-rod macromonomers of the presentinvention. In one embodiment, the macromonomer is added during thepolymer-forming reaction (polymerization) of the polymer to bestiffened. The polymer to be stiffened and/or strengthened will bereferred to as the flexible polymer, regardless of its absolutestiffness. In one embodiment, in addition to being rigid, themacromonomer will dissolve in the flexible polymer polymerization dopeand have functionality enabling it to take part in the polymerizationreaction. In another embodiment, the initially formed flexiblecondensation polymer is isolated, and a solvent is selected for both themacromonomer and the flexible polymer. The flexible polymer andmacromonomer are redissolved, and the macromonomer reacts with theoriginally formed flexible polymer. Macromonomers may also be dissolvedin the melt of the flexible polymer, where reaction of the side groupsmay then occur.

Several types of condensation polymers may be distinguished.Condensation polymers may include a single monomer, usually referred toas an A-B monomer: ##STR5##

Alternatively, two complementary difunctional monomers, usually referredto as A-A and B-B may be condensed: ##STR6##

Where the rigid-rod macromonomers are used in a condensationpolymerization, the reactive side groups can be considered to be the A-,or B- type end groups typically described in A-A, A-B, and B-B monomersused in condensation polymerization systems. A-A, B-B, and A-B typemonomers are described in U.S. Pat. No. 4,000,187 to Stille,incorporated herein by this reference.

Non-limiting examples of A-A and B-B type monomers include diamine-typemonomers such as p-phenylenediamine, m-phenylenediamine, oxydianiline,methylenedianiline, tetramethylenediamine, hexamethylenediamine, and thelike; diol-type monomers such as resorcinol and hexanediol;bisaminoketones, bisthiols, and the like; diacid-type monomers such asadipic acid, adipoyl chloride, esters of adipic acid, terephthalic acid,terephthaloyl chloride, esters of terephthalic acid, bisketomethylenes,bis(activated halides) such as chlorophenyl sulfone, and the like.

Non-limiting examples of A-B type monomers include amino acids, aminoacid esters, activated halides such as 4-fluoro-4'-hydroxybenzophenone,lactams (e.g., caprolactam), lactones, and the like.

Several types of reinforced polymers and copolymers are possible withthe rigid-rod macromonomers of the present invention. One skilled in theart will appreciate that the backbone of the macromonomers of thepresent invention, generally designated "M", can have A-type, B-type, orboth A- and B-type reactive side groups pendant therefrom. In otherwords, a given macromonomer can have reactive side groups that arecomplementary to A-type, B-type, and/or both A- and B-type condensationmonomers.

Macromonomers having "A" type reactive side groups, complementary to B-Band A-B type condensation monomers, may be used in the followingexemplary, and non-limiting, ways:

(a) Macromonomer+AA or BB→crosslinked polymer with short chains betweencrosslinks (FIG. 1);

(b) Macromonomer+AA+BB→crosslinked polymer with long chains betweencrosslinks; chain length between crosslinks is dependent on the amountsof A-A and B-B monomers (FIG. 2);

(c) Macromonomer+AB→flexible polymer chains grafted to rigid-rodsegments (FIG. 3);

(d) Macromonomers+AA+BB+preformed flexible polymer→semi-interpenetratingnetwork of uncrosslinked flexible polymer in a crosslinkedmacromonomer-AA-BB network (FIG. 4).

Order of addition and control of monomer imbalance can be used to createcomplex, crosslinked polymeric compositions. Any set of A-A, B-B and A-Bmonomers which will co-condense with the macromonomers of the presentinvention will be called complementary monomers. For example,terephthalic acid and ethylene glycol are complementary monomers thatwill condense with rigid-rod macromonomers having A-type reactive sidegroups (for example hydroxyalkyl or carboxylate side groups). Similarly,a co-polyester can be formed by condensing A-type macromonomers havingstructure (1) or (2) with one or more complementary monomers such asbiscarboxylic acids, biscarboxylic acid halides, biscarboxylic acidesters, bisdiols, hydroxycarboxylic acids, lactones, and the like.

Three variables which may be used to control the properties of thecopolymers prepared by incorporating the macromonomers of the presentinvention are: the average length of the rigid segments, L_(r), which isproportional to DP_(n), the average number of reactive side groups permacromonomer, and the weight fraction of rigid segments in thecopolymer, W_(r).

REINFORCING THERMOSET RESINS

The rigid-rod macromonomers of the present invention may also be used toform thermoset resins, either alone or in conjunction with existingthermoset formulas to impart strength, stiffness, and/or a lowercoefficient of thermal expansion. Thermosets are often formed in stages,where monomers are allowed to react to a limited extent to give aprocessable resin, which is cured in a second stage, often by heattreatment. Thermosets formed in accordance with the present inventionare typically highly crosslinked, and the stages are defined by thedegree of crosslinking. Aside from the insoluble, infusible nature ofthe resulting cured thermoset, the chemistry is similar to condensationpolymers.

It will often be desirable to use the rigid-rod macromonomers of thepresent invention with other small molecule crosslinkers, curing agents,additives, fillers, modifiers and the like. Diols, polyols, diamines andpolyamines are commonly used thermoset precursors that will react withthe macromonomers of the present invention. A non-limiting example ofthe use of such compounds is the formation of a two part thermosettingresin, wherein Part 1 is primarily comprised of a rigid-rodmacromonomer, and Part 2 is primarily comprised of a curing agent suchas a diamine, or a catalyst. Two part resins often have longer shelflives, because each component alone is relatively unreactive.

Rigid-rod polymers heretofore have not been used in thermosets,primarily because it is commonly thought that rigid-rod polymers are notsoluble in resin systems, including solutions of resins or pre-polymersused to prepare thermoset resins. The rigid-rod macromonomers of thisinvention, however, are soluble in common solvents and can be madecompatible with various resin systems by proper choice of solubilizingside groups. The reactive side groups also should be compatible with thecure chemistry of the thermoset.

Typically, but not necessarily, the reactive side groups will be chosento match the reactive groups in the thermoset. For example, reactiveside groups should be epoxy groups, phenol groups, or amino groups foruse with an epoxy resin, or phenol groups for use with phenolic resins.It is also usually desirable for the cure temperatures of the reactiveside groups and the thermoset to be similar. Non-limiting examples ofthermoset systems which can incorporate the rigid-rod macromonomers ofthe present invention are: allyl resins, benzophenonetetracarboxylicacid or its anhydride, bisacetylene resins, bisbenzocyclobutene resins,bisbiphenylene resins, bisphenoltetracarboxylic acid, or its anhydride,diepoxides, epoxy resins, formaldehyde, paraformaldehyde,paraformaldehyde-based resins, furan resins, phenolic resins,polyepoxides, trioxanes, phenol-formaldehyde resins, novolac resins,resole resins, resorcinol-formaldehyde resins, silicone resins,urethanes, melamine resins, isocyanate resins, resins based on cyanuricacid and cyanuric chloride, polyamic acids, polyamide resins,crosslinked polyamides and polyesters, unsaturated polyester resins,urea resins, vinyl ester resins, and natural resins, gums, lacquers andvarnishes.

The rigid-rod macromonomers of the present invention may also be usedalone to form thermosetting resins. In this case, the side groups G arenot needed for solubility in, or compatibility with, other resins,polymers or monomers, but impart some degree of thermoformability. Ingeneral, rigid-rod macromonomers with a lower degree of polymerization,smaller n will have lower glass transition temperatures and meltingtemperatures and will be more readily heat processed. As is known in theart it is necessary to adjust the melting temperature and curetemperature so that the polymer system does not cure before it isthermoformed, and so that unreasonably high temperatures are not neededfor curing.

When used as a thermoset, the rigid-rod macromonomer must havesufficient flow properties to be shaped or processed, typically atelevated temperatures. Thus, the side groups G and the DP_(n) are chosento allow some degree of thermoformability. In general, larger and moreflexible G's increase processability, as does lower D_(n) On the otherhand, smaller G's and larger DP_(n) 's enhance stiffness and strength,so that optimum sizes for DP_(n) and G can be found. Differentprocessing methods will have different requirements; for example,sintering does not require complete melting, whereas injection moldingrequires low viscosity melts. The reactive side groups of a rigid-rodmacromonomer used as a thermoset should have a cure temperatureconsistent with the required processing temperature. If the curetemperature is too low, the material will cure before processing can becompleted. If the cure temperature is too high, the material may notfully cure or the flow properties at the curing temperature may beundesirable. In an exemplary and non-limiting embodiment of theinvention, cure is effected by using a curing agent such as a catalystor low molecular weight crosslinking agent.

Non-limiting examples of reactive side groups with good curetemperatures are maleimides, nadimides, and acetylenes.

REINFORCING ADDITION POLYMERS

The rigid-rod macromonomers of the present invention also find use aspro- and post-polymerization additives. As Post-polymerizationadditives, rigid-rod macromonomers may be used in compounding, blending,alloying, or otherwise mixing with preformed polymers, preformed blends,alloys, or mixtures of polymers. In these cases the solubilizing sidegroups and/or reactive side groups help make the macromonomer compatiblewith the polymer to be reinforced. Such compounding, blending, alloyingetc. may be done by solution methods, melt processing, milling,calendaring, grinding or other physical or mechanical methods, or by acombination of such methods. Chemical reaction of the reactive sidegroups of the macromonomer with the polymer into which the macromonomeris being incorporated may take place during such processes, or thereactive side group may simply serve to make the rigid segment Mcompatible with the preformed polymer, for example via non-covalentinteractions including hydrogen bonding, ionic bonding and van der Waalsforces. Mechanical heating or shearing can initiate such chemicalprocesses which will effect the final composition.

For many addition polymers, where it is not convenient to introduce themacromonomer during polymerization, the rigid-rod macromonomer may beintroduced by the above methods in post-polymerization processes.Non-limiting examples of such polymers include, polyethylene,polypropylene, polyvinylchloride, polystyrene, polyacrylonitrile,polyacrylates, acrylonitrile-butadiene-styrene (ABS), styrene butadienerubber (SBR), and other homopolymers, copolymers, blends, alloys etc. Amacromonomer having reactive side groups that act as initiators foraddition polymerization can be used to prepare graft copolymers having arigid-rod main chain and flexible side chains (FIG. 5).

A macromonomer having reactive side groups that act as addition typemonomers, for example styrene side groups, may be used to form additionpolymers having rigid-rod segments (FIG. 6). Depending on concentrationsand reactivity of reactants, the resulting addition polymers willexhibit varying degrees of crosslinking.

The rigid rod macromonomers of the present invention may be used in anyof the various types of polymerization processes, including but notlimited to, bulk polymerization, suspension polymerization, emulsionpolymerization, reaction injection molding, reinforced reactioninjection molding, resin transfer molding and the like.

Other applications will be apparent to those skilled in the art.

As pre-polymerization additives, the macromonomers of the presentinvention are added along with other monomers to be polymerized to yieldthe final polymer.

Optionally, conventional fillers such as carbon black, silica, talc,powders, chopped or continuous fibers, or other macroscopic reinforcingagents as are known in the art can be added to the polymer systems whichincorporate the rigid-rod macromonomers of the present invention. Inembodiments of the invention in which macroscopic reinforcing agents areadded, the macromonomers of the present invention add additionalstrength, stiffness, creep resistance, fire resistance toughness and/orother properties to what would otherwise be conventional composites andresins and also serve to decrease the amount of filler used in aconventional composite or resin.

The rigid rod macromonomers of the present invention may be used toenhance the properties of all types of natural and synthetic polymers,including but not limited to, addition polymers, condensation polymers,ring opening polymers, thermosets, thermoplastics, elastomers, rubbers,silicones, silicone rubbers, latexes, gums, varnishes, and cellulosederived polymers.

When used with rubbers and elastomers having a polymer network the rigidrod macromonomers act to modify such properties as strength, abrasionresistance, resilience, wear resistance, creep and the like, and may beused to replace or eliminate the use of fillers.

The reinforced polymers of the present invention may be used tofabricate films, fibers, and molded parts having improved properties,especially improved mechanical properties, relative to the same materialwithout reinforcement by rigid-rod macromonomers. Other non-limitingexamples of applications of the reinforced polymers of the presentinvention include adhesives, elastomers, coatings, membranes, plasticsheet, and sheet molding compounds.

The reinforced polymers of the present invention may contain in additionto rigid-rod segments conventional additives, including but not limitedto, plasticizers, flame retardants, smoke supressants, fillers,additional polymers, compatibilizers, lubricants, surface modifiers,antioxidants, dyes and pigments, surfactants, biodegradabilityenhancers, biomodifiers, UV absorbers and the like.

METHODS FOR PREPARING MACROMONOMERS HAVING REACTIVE SIDE GROUPS

In order to introduce rigid segments into a wide variety of polymers,polymeric compositions, ceramics, glasses, and the like, a rigid-rodtype macromonomer is first prepared. The poly-1,4-phenylene structure(1) and aza derivatives (structure (2)) offer a stiff, strong, thermallystable, and chemically inert backbone, of potentially low cost. Pendentside groups impart solubility and reactivity to the macromonomer.

Several methods may be used to prepare substituted Poly-para-phenylenesand aza analogs. The simplest rely on reductive condensation of1,4-dihaloaromatics, either by way of a Grignard reagent, or directly. Acatalyst, such as bis(triphenylphosphine) nickel (II) chloride or1,4-dichloro-2-butene is used. Para-bromoaryl boronic acids may becoupled using palladium based catalysts. Polyphenylenes have also beenprepared by methods which do not give exclusive para linkage, such asDieis-Alder condensation of bis-acetylenes and bis-pyrones,polymerization of 1,3-cyclohexadiene followed by aromatization andoxidative polymerization of benzene.

If the macromonomer is prepared using a transition metal catalyst, andthe synthesis proceeds through metallo-terminated chains asintermediates, the molecular weight of the resulting macromonomer may becontrolled by the catalyst-to-monomer ratio. In this case thepolymerization will cease when the number of chain ends (capped withcatalyst) equals the number of catalyst molecules initially present. TheDP_(n) will equal twice the monomer to catalyst ratio. End groups (notshown in the structures provided herein) then may be introduced byadding reagents which displace the metallo end groups. For example, ifthe macromonomer is worked-up in an alcohol, the metal groupsterminating the chains of the macromonomer are displaced by protons (H).The metallo-terminated macromonomer is thereby quenched.

Macromonomers of the present invention may have, in addition to reactiveside groups, reactive end groups. Macromonomers having reactive endgroups may be prepared, for example, by adding endcappers during thecoupling reaction, or by displacing the metallo end groups with anendcapper. The endcappers may themselves be reactive groups or protectedforms of reactive groups.

The rigid-rod macromonomers of the present inventicn may be made bythese and other methods, keeping in mind the special requirements ofsolubilizing and reactive side groups. The catalytic reductive couplingof 1,4-dihaloaryls is preferred, (and more preferably, reductivecoupling of 1,4-dichloroaryls) because of its simplicity and widertolerance of functional groups. The special nature of the rigid-rodmacromonomers of the present invention must be taken into account inorder to successfully prepare these macromonomers.

Rigid-rod macromonomers comprised of both monomer units bearingsolubilizing side groups and monomer units bearing reactive side groupsare conveniently prepared by either of two different routes. Oneapproach is to copolymerize two or more different monomers, at least oneof which bears one or more reactive side groups. A non-limiting exampleis copolymerization of a 19:1 molar ratio of 2,5-dichlorobenzophenoneand methyl-2,5-dichlorobenzoate to yield a macromonomer having astructure (4): ##STR7## where x≈95%, y≈5% and the monomer units bearinga reactive ester group are randomly distributed amongst the monomerunits bearing a solubilizing benzoyl group.

A second approach is to first prepare a homopolymer and then react anexcess of said homopolymer with a predetermined amount of a reagent toyield a partially modified polymer that is, in effect, a copolymer. Anon-limiting example is polymerization of 2,5-dichlorobenzophenone toyield parapolybenzoylphenylene, followed by treatment with apredetermined amount of methyl lithium, followed by hydrolysis to yielda macromonomer having the structure (5): ##STR8## where n+m=100%, andthe monomer units bearing a reactive benzylhydroxy side group arerandomly distributed amongst the monomer units bearing a solubilizingbenzoyl group.

A second non-limiting example of side chain modification is thetreatment of parapolybenzoylphenylene with a predetermined amount ofphenol in the presence of a Lewis acid catalyst to give a macromonomerhaving the structure (6): ##STR9## where x+y=100% and the monomer unitsbearing a reactive (and solubilizing) phenolic side group are randomlydistributed amongst the monomer units bearing a solubilizing benzoylgroup.

The synthesis of even short rigid-rod molecules is made difficult bytheir low solubility. For example, poly-1,4-phenylene (structure (1),where G₁ through G₄ and E are each hydrogen) compounds with n greaterthan about 8 are essentially insoluble in all solvents and areinfusible. Solubility is achieved in the present invention byappropriate choice of side groups G, bearing in mind the solvent systemsto be employed. For example, for polar aprotic solvents, such asdimethylformamide or N-methylpyrrolidone, polar aprotic side groups suchas amides and ketones are appropriate. For protic solvents, e.g. water,acids or alcohols, ionizable side groups, e.g. pyridyl or sulfonate,might be considered.

The side groups may also act to twist the main chain phenylene units outof planarity (although the main chain remains straight and not coiled).Phenylene pairs with substituents at the 2,2' positions will be twistedout of planarity by steric repulsion. Since planar phenylene chains packmore efficiently, a twisted chain will be more soluble. One means ofsolubilizing rigid-rod molecules is to provide adjacent phenylene pairswith substituents ortho with respect to the other phenylene of the pair.Even occasional 2,2' side groups will disrupt packing and enhancesolubility. Another means of improving solubility is to decrease theorder (increase the entropy) of the side groups, for example by a randomcopolymer with two or more different types of substituents. Othermechanisms of increasing solubility may also be possible.

Non-limiting examples of solubilizing side groups are: phenyl, biphenyl,naphthyl, phenanthryl, anthracenyl, benzyl, benzoyl, naphthoyl, phenoxy,phenoxyphenyl, phenoxybenzoyl, alkyl, alkyl ketone, aryl, aryl ketone,aralkyl, alkaryl, alkoxy, aryloxy, alkyl ester, aryl ester (esters maybe C-bound or O-bound), amide, alkyl amide, dialkyl amide, aryl amide,diary amide, alkyl aryl amide, amides of cyclic amines such aspiperidine, piperazine and morpholine (amides may be CO-bound orN-bound), alkyl ether, aryl ether, alkyl sulfides, aryl sulfides, alkylsulfones, aryl sulfones, thioethers, fluoro, trifluoromethyl,perfluoroalkyl, and pyridyl, where alkyl is a linear or branchedhydrocarbon chain having between 1 and 30 carbon atoms, and aryl is anysingle, multiple or fused ring aromatic or heteroaromatic group havingbetween 3 and 30 carbon atoms. Fluorine-substituted analogs of theabove-identified side groups may also be used.

G₁ and G₂, and/or G₃ and G₄ may be interconnected to form bridginggroups. Non-limiting examples of such groups and the monomer units thatresult are shown below: ##STR10## Solubilizing side groups G may also beoligomeric cr polymeric groups. Using side groups which are functionallyequivalent to the flexible polymer to be strengthened increases thecompatibility of the rigid segments with the flexible segments. Anon-limiting example is the use of a macromonomer denoted "M_(oligo), "bearing oligocaprolactam side groups G, as a comonomer with caprolactamin the preparation of poly(hexamethyleneadipamide-co-M_(oligo)).

For cases where the monomer unit of the macromonomer is unsymmetricalabout the plane perpendicular to the polymer axis and centered on themonomer unit, for example if G₁ is benzoyl and G₂, G₃, and G₄, arehydrogen, isomeric forms of the macromonomer exist. The monomers canlink exclusively head-to-tail to form a regular structure. The monomerscan also form a regular structure by linking exclusively head-to-headand tail-to-tail. Other more complicated structures and a randomstructure are also possible. The particular monomers and conditions usedto form the macromonomer will determine the detailed structure. As usedherein, structures (1), (2) and (3) represent all isomeric cases, eitherregular or random. Similarly, macromonomers of the type depicted instructures (4)-(6) are not limited to the particular isomers showntherein.

It will sometimes be desirable to include 1,4-dichlorobenzene as acomonomer, so that some monomer units will be unsubstituted, i.e., G₁═G₂ ═G₃ ═G₄ ═H. The unsubstituted units will lower cost, but may alsolower solubility.

REACTIVE SIDE GROUPS

The reactive side groups, G, are chosen to allow chemical interactionwith the flexible polymer or inorganic matrix to be stiffened orstrengthened.

Reactive side groups can be further derivatized to provide additionalfunctionality, as for example during deprotection, or transformation ofone reactive group into another, for example reduction of a nitrile intoan amine, an aldehyde into an alcohol, or conversion of an amine into animine. More than one type of reactive side group may be present.

Amines form an important class of reactive side groups.Amine-functionalized macromonomers can be used with polyamides,polyimides, polyimidamides, polyureas, polyimines, and other polymersderived from bisamine monomers. Amine-functionalized macromonomers canalso be used with polymers not derived from bisamine monomers, such asepoxides and polyesters; in the latter case the macromonomer would beincorporated into the polyester chain via amide links. Preparation ofthe amine-functionalized macromonomers can involveprotection/deprotection of the amine groups, for example as asuccinimide or an amide.

The following are non-limiting examples of amine derived reactive sidegroups: amino, aminoalkyl, aminoaryl, aminoalkaryl, aminoaralkyl,aniline, C-alkylaniline, N-alkylaniline, aminophenoxy, and aminobenzoyl.Other substituted and/or chemically protected aniline side groups mayalso be used. The following structures illustrate non-limiting examplesof amine-derived reactive side groups. Typical amines, amino alkyls, andamino aralkyls are given by the following structures (7a-7c): ##STR11##where R₁ and R₂ may be independently chosen from: hydrogen, alkyl, aryl,alkaryl, aralkyl, alkylketone, arylketone, alkyl ether or arylether,where alkyl and aryl are as defined above, x ranges from one to abouttwenty, and Z is a difunctional group chosen from: nil, phenyleneoxy,ketophenylene, phenylenesulfone, -O-, -NH-, keto, -SO₂ -, aryl, alkyl,alkaryl, or aralkyl. R₁ and R₂ include bridging groups, such as --CH₂CH₂ CH₂ CH₂ CH₂ --, --CH₂ CH₂ OCH₂ CH₂ --, and --CH₂ CH₂ CH₂ CO--. R₁and R₂ will often be used as protecting groups, to be removed at a laterstage of processing, and as such include common amine and alcoholprotecting groups, non-limiting examples of which are: trimethylsilyl,trityl, tetrahydropyranyl, tosyl, methoxyisopropylidene, imide, imine,amide, ester, and the like.

Typical amino aryl reactive side groups, G, have the structures (8a-8c):##STR12## where Z, R₁ and R₂ are as defined above, and R₃ -R₆ areselected from the same group as R₁ and R₂. Aniline side groups have theabove structure where Z is nil and the R's are all hydrogen.

Aminophenoxyphenyl and aminobenzophenone side groups have the generalstructures (9a and 9b): ##STR13## where R₁ and R₂ are as defined above.

Imides comprise a second class of reactive side groups. The maleimidesare represented by the structures 7a-9b, where R₁ and R₂ together equalthe bridging group --COCH═CHCO--. Bismaleimides are commerciallyvaluable in thermoset resins. Rigid-rod macromonomers with maleimide endgroups are useful for strengthening conventional bismaleimide resins.They may also be used alone as novel bismaleimide resins containingrigid-rod elements. Other reactive imide end groups are contemplated bythe present invention, including the nadimide end groups. Unreactiveimides may also be used; succinimide may be used as a protected form ofamine.

Closely related to the amines are the amides. In structures 7a-9b, if R₁or R₂ ═-COalkyl or -COaryl, the reactive side groups are amides. If R₁or R₂ ═-COCH═CH₂, the reactive side groups are acrylamides.Amide-functionalized macromonomers are also useful in reinforcingpolyamides, such as nylon. Amide groups may react by transamination withthe flexible polymer during polymerization or compounding.

Another important class of reactive side groups are alcohols and ethers.Diol-functionalized macromonomers may be used as comohomers with otherdiol monomers. Polyesters, polycarbonates, urethanes, and polyethers arenon-limiting examples of polymers prepared from diols. Alcoholmacromonomers may also be used in non-diol derived polymers, forexample, polyamides, where linkage to the macromonomer is through esterlinks. Both the amine macromonomers and the alcohol macromonomers may beused to replace dibasic monomers, in general, in condensationpolymerizations.

Non-limiting examples of alcohol-functionalized macromonomers are:hydroxy, hydroxyalkyl, hydroxyaryl, hydroxyalkaryl, hydroxyaralkyl,phenol, C-alkylphenol, O-alkylphenol, hydroxyphenoxy, andhydroxybenzoyl. The following non-limiting structures (10a-10c)illustrate exemplary alcohol side groups: ##STR14## where R₁, x and Zare as defined in the discussion following structures (7a-7c).

The following structures (11a-11c) are representative of phenolic sidegroups: ##STR15## where R₁ -R₆, and Z are as defined above.

The following structures (12a-12c) are more specific examples of theabove structures: ##STR16## where R₁ is as defined above.

For R₁ ═H, the structures (12a-12c) represent phenol,hydroxyphenoxyphenyl, and hydroxybenzophenone side groups, respectively.For R₁ ═ketoalkyl or ketoaryl, the structures (12a-12c) arephenylesters. R₁ may contain additional reactive groups, such asacrylate or vinyl. In structures 9a through 11c, for R₁ ═--COCH═CH₂ thereactive side groups are acrylates, for R₁ ═--CH═CH₂ the reactive sidegroups are vinyl ethers.

Carbonyl-containing reactive side groups including acetyl, formyl,carboxy, ester, amide, acrylate, ketoalky and ketoaryl are representedby the structures (12a-12d) where Y is CH₃, H, OH, OR₁, NR₁ R₂, vinylalkyl and aryl respectively, and R₁ -R₆ and Z are as defined above.Amides may be C or N bound; see structures 6a-8b above. ##STR17##Macromonomers of the present invention having carboxy side groups may beused to reinforce polyesters and polyamides.

Acetylene side groups have the structures (14a-14d) where Y is -CCH.Olefin side groups have the structures (14a-14d) where Y is --CH═CH₂.Halide, cyano, cyanate, and isocyanate side groups have the structures(14a-14d) where Y is -halogen, -CN, -OCN and -NCO respectively.##STR18##

Reactive side groups may also be strained ring compounds includingepoxides, biphenylenes and benzocyclobutenes.

In situations where the reactive side groups G are reactive with eachother, both the reactive side groups G and the groups on the flexiblepolymer or monomer with which they are ultimately to react should beselected so that the relative rates of reaction are approximately equal.This will enhance the randomness of the distribution of the macromonomerwithin the final polymer.

When the rigid-rod macromonomers of the present invention are used aspre-polymerization additives, they are preferably added in an amountsuch that W_(r) ranges from 1 percent to 60 percent, i.e., the rigid-rodmacromonomers make up from 1 percent to 60 percent of the weight of theresulting polymeric material. Such a range takes into account the tradeoff between increased cost and decreased processibility that results asthe value of W_(r) increases in magnitude. In practice, it is desirableto experimentally determine the optimal weight fraction required forparticular applications.

In certain circumstances, it may be desirable for W_(r) to exceed 60percent of the total weight of the copolymeric material. For instance,when the rigid-rod macromonomers of the present invention are used aloneas thermosetting resins, W_(r) can approach the limiting value of 100percent, depending on the size, frequency, and orientation of thecrosslinking groups formed during curing.

There will also be an optimal range for L_(r) r, typically between 8 and500 repeat units, beyond which additional increases in length will havelittle further effect on strength or stiffness but will reduceprocessibility. Optimal ranges for both W_(r) and L_(r) can be readilydetermined by one skilled in the art.

The aspect ratio of the macromonomers incorporated into copolymers alsoaffects the physical properties of the copolymers, particularly theprocessibility thereof. The aspect ratio of a macromonomer is defined tobe the length to diameter ratio of the smallest diameter cylinder whichwill enclose the macromonomer segment, including half the length of theterminal connecting bonds, including hydrogen but not any other attachedside groups, such that the axis of the cylinder is parallel to theconnecting bonds in the straight segment.

For rigid-rod polyphenylenes, and aza analogs, the aspect ratio isapproximately equal to the DP_(n), because the phenylene monomer unithas an aspect ratio of about one.

When the average aspect ratio of the macromonomers is less than about 7or 8, the macromonomers typically do not impart the desired strength andstiffness into the final polymer. As the aspect ratio is increased, themechanical properties of the reinforced polymer improve. All otherfactors being equal, a longer rigid segment will provide a greaterincrease in stiffness than a shorter rigid segment. This is true forreinforcement of any geometrical type of polymer, e.g., linear,branched, crosslinked, and the like. It is known in the art that forconventional fiber-containing composites mechanical properties improverapidly up to aspect ratios of about 100, after which there are lesserimprovements. A similar situation has been found to exist for rigid-rodmacromonomers.

Although mechanical properties of the polymers improve as the aspectratio increases, processing becomes more difficult. Viscosities ofpolymer solutions are dependent on the DP_(n) of the polymer.Viscosities of rigid-rod polymers increase much more rapidly with DP_(n)than viscosities of flexible polymers. Similarly, melt viscosities offlexible polymers reinforced with rigid-rod polymers increase with theDP_(n) of the rigid segments, making thermal processing more difficultas DP_(n) increases.

There is generally a trade-off between improved mechanical propertiesand difficulty of processing, resulting in an optimal aspect ratio andDP_(n) for the rigid-rod macromonomers. For example, if it is desired toincrease the modulus of a flexible polymer reinforced with rigid-rodmacromonomers, the aspect ratio of the macromonomer could be increased,but the melt and solution viscosity will increase and solubility of therigid-rod macromonomer will decrease, making processing and preparationmore difficult. DP_(n) 's of about 100 are often optimal; however,higher or lower DP_(n) 's may sometimes be desirable.

SYNTHETIC METHODS

The following synthetic procedures are exemplary methods that may beused in the preparation of precursors to, and reagents used in thesynthesis of, the rigid-red macromonomers of the present invention; anexemplary method of preparing succinimide-protected amines; and a methodfor deprotecting protected side groups. The choices and amounts ofreagents, temperatures, reaction times, and other parameters areillustrative but are not considered limiting in any way. Otherapproaches are contemplated by, and within the scope of, the presentinvention.

Preparation of 2,5-Dichlorobenzoyl Compounds

2,5-dichlorobenzoyl-containing compounds (e.g. 2,5-dichlorobenzophenonesand 2,5-dichlorobenzamides) can be readily prepared from 2,5dichlorobenzoylchloride. Pure 2,5-dichlorobenzoylchoride is obtained byvacuum distillation of the mixture obtained from the reaction ofcommercially available 2,5-dichlorobenzoic acid with a slight excess ofthionyl chloride in refluxing toluene. 2,5-dichlorobenzophenones(2,5-dichlorobenzophenone, 2,5-dichloro-4'-methylbenzophenone,2,5-dichloro-4'-methoxybenzophenone, and2,5-dichloro-4'-phenoxybenzophenone) are prepared by the Friedel-Craftsbenzoylations of benzene and substituted benzenes (e.g. toluene,anisole, diphenyl ether, respectively), with 2,5-dichlorobenzoylchorideat 0°-5° C. using 2-3 mole equivalents of aluminum chloride as acatalyst. The solid products obtained upon quenching with water arepurified by recrystallization from toluene/hexanes.2,5-dichlorobenzoylmorpholine and 2,5-dichlorobenzoylpiperidine areprepared from the reaction of 2,5-dichlorobenzoylchloride and eithermorpholine or piperidine, respectively, in toluene with pyridine addedto trap the HCl that is evolved. After washing away the pyridinium saltand any excess amine, the product is crystallized from the toluenesolution.

Preparation of Activated Zinc Powder

Activated zinc powder is obtained after 2-3 washings of commerciallyavailable 325 mesh zinc dust with 1 molar hydrochloric acid in diethylether (anhydrous) and drying in vacuo or under inert atmosphere forseveral hours at abut 100°-120° C. This material should be usedimmediately or stored under an inert atmosphere away from oxygen andmoisture.

Preparation of Succinimide Protected Amines

The dry amine (0.5 mole) and succinic anhydride (0.5 mole) are dissolvedin 2 L dry toluene. Catalyst, p-toluenesulfonic acid (0.01 mole), isthen added and the mixture is held at reflux for 24 hours, using aDean-Stark trap to collect water. After cooling, the product isprecipitated with diethyl ether, filtered, washed with ether and dried.

Deprotection of Protected Side Groups

In the cases where the functional side groups are protected as an imide,amide, or ester, the protecting groups are removed as follows: Theprotected macromonomer is suspended in 25 ml of 10% HCl in ethanol andheated to reflux for six to twelve hours. This mixture is neutralizedwith sodium hydroxide, filtered, washed and dried. Further purificationby dissolution and precipitation by adding a non-solvent may beeffected.

The following specific examples of preparing rigid-rod macromonomers andpolymers containing rigid-rod macromonomers are illustrative of thepresent invention, but are not considered limiting thereof in any way.

EXAMPLE 1. Preparation of a macromonomer of the structure: ##STR19##

Anhydrous bis(triphenylphosphine) nickel(II) chloride (0.25 g; 0.39mmol), triphenylphosphine (0.60 g; 2.29 mmol), sodium iodide (0.175 g,1.17 mmol) and 325 mesh activated zinc powder (1.2 g; 18.4 mmol) areplaced into a flask under an inert atmosphere along with 7 ml ofanhydrous N-methylpyrrolidinone (NMP). This mixture is stirred for about10 minutes at room temperature, leading to a deep-red coloration. Asolution of 2,5-dichlorobenzophenone monomer (3.26 g; 12.98 mmol) and ofmethyl-2,5-dichlorobenzoate comonomer (0.14 g; 0.68 mmol) in 8 ml ofanhydrous NMP is then added by syringe. After stirring for about 12hours at 50°-60° C., the resulting viscous solution is poured into 100ml of 1 molar hydrochloric acid in ethanol to dissolve the excess zincmetal and to precipitate the functionalizod copolymer. This suspensionis filtered and.the precipitate triturated with acetone and dried toafford a light yellow to white powder. Approximately 5% of the sidechainappendages of the resulting rigid-rod copolymer contain reactive estergroups. Even greater reactivity may be imparted by hydrolyzing the estergroups to carboxy groups (e.g. by refluxing in 10% HCl in ethanol forsix to twelve hours and then neutralizing with sodium hydroxide).

EXAMPLE 2. Preparation of a macromonomer of the structure: ##STR20##

The procedure of Example 1 is followed, where the comonomer is4'-acetoxy-2,5-dichlorobenzophenone (0.20 g; 0.65 mmol). Approximately5% of the sidechain appendages of the resulting rigid-rod copolymercontain reactive ester groups. Even greater reactivity may be impartedby hydrolyzing the ester groups to phenolic groups (e.g. by refluxing in10% HCl in ethanol for six to twelve hours and then neutralizing withsodium hydroxide).

4'-Acetoxy-2,5-dichlorobenzophenone is prepared treating4'-Hydroxy-2,5-dichlorobenzophenone, which is prepared by theFriedel-Crafts acylation of phenol with 2,5-dichlorobenzoyl-chloride,with acetyl chloride.

EXAMPLE 3 Preparation of a macromonomer of the structure: ##STR21##

The procedure of Example 1 is followed where the comohomer is2,5-dichlorophenylsuccinimide (0.17 g; 0.70 mmol). The isolated materialis refluxed in 10% HCL in ethanol for six hours and then neutralizedwith sodium hydroxide. Approximately 5% of the sidechain appendages ofthe resulting rigid-rod copolymer contain reactive amine groups.

EXAMPLE 4 Preparation of a macromonomer of the structure: ##STR22##

The procedure of Example 1 is followed, where the comohomer is thetetrahydropyranyl ether of 2,5-dichlorophenol (0.17 g; 0.69 mmol). Theisolated material is refluxed in 10% HCL in ethanol for six hours andthen neutralized with sodium hydroxide. Approximately 5% of thesidechain appendages of the resulting rigid-rod copolymer containreactive hydroxy groups.

EXAMPLE 5 Preparation of a macromonomer of the structure: ##STR23##

A solution of parapolybenzoylphenylene (0.5 g; 2.8 mmol of monomerunits) in 50 ml of diphenyl ether is treated with 0.2 ml (0.28 mmol) of1.4 molar methyl lithium (ether solution) and heated at 100° C. for 2-3days. This mixture is poured into 1 molar sulfuric acid in ethanol tohydrolyze the lithio salt and precipitate the product. Approximately 10%of the sidechain appendages of the resulting rigid-rod copolymer containreactive hydroxy groups.

Parapolybenzoylphenylene is prepared as follows: Anhydrous bis(triphenylphosphine) nickel (II) chloride (0.25 g; 0.39 mmol) ,triphenylphosphine (0.60 g; 2.29 mmol), sodium iodide (0.175 g; 1.17mmol), and 325 mesh activated zinc powder (1.3 g; 20 mmol) are placedinto a flask under an inert atmosphere along with 7 ml of anhydrousN-methylpyrrolidinone (NMP). This mixture is stirred for about 10minutes at room temperature, leading to a deep-red coloration. Asolution of 2,5-dichlorobenzophenone monomer (4.0 g; 16 mmol) in 8 ml ofanhydrous NMP is then added by syringe. After stirring for about 12hours at 50°-60° C., the resulting viscous solution is poured into 100ml of 1 molar hydrochloric acid in ethanol to dissolve the excess zincmetal and to precipitate the polymer. This suspension is filtered andthe precipitate triturated with acetone and dried to afford a lightyellow to white powder.

EXAMPLE 6 Preparation of a macromonomer of the structure: ##STR24##

A solution of parapolybenzoylphenylene (1.0 g; 5.6 mmol of monomerunits) in 100 ml of diphenyl ether is treated with 0.25 ml (0.5 mmol) of2 molar sodium cyclopentadienide (tetrahydrofuran solution) and heatedat 100° C. for 4 hours. This mixture is poured into 1 molar hydrochloricacid in ethanol to precipitate the product. Approximately 9% of thesidechain appendages of the resulting rigid-rod copolymer containreactive fulvene groups.

EXAMPLE 7 Preparation of a macromonomer of the structure: ##STR25##

A solution of parapolybenzoylphenylene (0.5 g; 2.8 mmol of monomerunits) in 50 ml of methylene chloride is treated with 0.1 g (0.29 mmol)of 50% 3-chloroperoxybenzoic acid (MCPBA) and refluxed for 7 days. Thismixture is poured into acetone to precipitate the product. Approximately10% of the sidechain appendages of the resulting rigid-rod copolymercontain reactive ester groups.

EXAMPLE 8 Preparation of a macromonomer of the structure: ##STR26##

A solution of parapolybenzoylphenylene (0.5 g; 2.8 mmol of monomerunits) and 4-nitroaniline (25 mg; 0.18 mmol) in 50 ml of NMP is refluxedfor 48 hours. This mixture is poured into ethanol to precipitate theproduct. Approximately 6.5% of the sidechain appendages of the resultingrigid-rod copolymer contain reactive nitro groups.

EXAMPLE 9 Preparation of a macromonomer of the structure: ##STR27##

A mixture of parapolytoluoylphenylene (0.5 g; 2.6 mmol of monomer units)and potassium permanganate (0.16 g; 1.0 mmol) in 50 ml of glacial aceticacid is refluxed for 18 hours. This mixture is poured into ethanol, andthe product removed by filtration. Approximately 10-20% of the sidechainappendages of the resulting rigid-rod copolymer contain reactive carboxygroups.

Parapolytoluoylphenylene is prepared in the same manner asparapolybenzoylphenylene, except that a solution of2,5-dichloro-4'-methylbenzophenone monomer in anhydrous NMP is used inplace of 2,5-dichlorobenzophenone.

EXAMPLE 10 Preparation of a macromonomer of the structure: ##STR28##

A solution of parapolybenzoylphenylene (500 g; 2.78 mol of monomerunits), 4-aminophenol (30 g; 0.278 mol), and p-toluenesulfonic acidmonohydrate (1.9 g; 0.01 mol) in chlorobenzene (5 l) is heated to 80° C.for 48 hrs. This mixture is poured into ethanol to precipitate theproduct. Approximately 10% of the sidechain appendages cf the resultingrigid-rod copolymer contain reactive phenol groups.

EXAMPLE 11 Preparation of a nylon-6/polyparaphenylene graft copolymer.

The procedure of Kohan for the preparation of poly-ε-caprolactam(Nylon-6) given in Macromolecular Synthesis, J. A. Moore, Ed., JohnWiley & Sons; New York (1977), Coll. Vol. 1, pp. 91-94 (incorporatedherein by this reference), is followed, except that 2.5 g of theester-functionalized macromonomer of Example 1 is added along with theε-caprolactam. More specifically, a 38×300 mm Pyrex® test tube fittedwith 8 mm Pyrex® inlet and exit tubes is charged with ε-caprolactam (50g), the ester-functionalized macromonomer of Example 1 (2.5 g), and a50% by weight aqueous solution of an amine salt as catalyst. The tube isswept with nitrogen for 5 minutes, after which the nitrogen flow rate isadjusted to 350 cc. per minute. The tube is immersed to a depth of 9inches in a 280°-285° vapor bath. After 4 hours, the test tube isremoved from the bath and allowed to cool to room temperature. A polymerplug, which can be cut to a desired particle size, is obtained bybreaking the test tube away from the polymer. The polymer can then beextracted. The resulting resin is approximately 5% by weight rigid-rod.

A 50% by weight aqueous solution of an amine salt catalyst is preparedby dissolving or dispersing in water an amine, such ashexamethylenediamine, piperazine, 3,3'(methylimino)bispropylamine,3,3'-iminobispropylamine, m-xylylene diamine, and the like; dissolvingor dispersing in water an acid, such as adipic acid, sebacic acid, andthe like; and then slowly adding one solution to the other. Impuritiescan be removed by treating the resulting solution with Darco G-60, andthe filtrate can be used directly as the catalyst. Stoichiometricequivalents of the amine and acid are used, unless the amine is somewhatvolatile, in which case a 1% excess of the amine is used. Amino acidsare also suitable for preparation of an amine salt catalyst.

EXAMPLE 12 Preparation of an aromatic polyester-derived graft copolymer.

In a flamed 500 ml flask equipped with a magnetic stirrer, 9.931 g(43.50 mmol) of bisphenol-A, 8.894 g (43.81 mmol) of isophthaloyldichloride, 2.362 g (0.62 mmol of phenolic groups) of the phenolicfunctionalized macromonomer of Example 1, and 15 ml of pyridine in 100ml of tetrachloroethane are added under nitrogen pressure and heated at120° C. for 20 hours. The copolymer is precipitated in methanol,filtered, redissolved in chloroform, reprecipitated in methanol,filtered, and dried at 80°-100° C. in vacuo. The resulting graftcopolymer is approximately 13% by weight rigid-rod.

EXAMPLE 13 Preparation of an epoxy resin containing a rigid-rodmacromonomer.

The macromonomer of Example 9 (10 g) is mixed with the diglycidyl etherof bisphenol-A (150 g) (EPON 825, commercially available from ShellChemical Co.) with warming. After the macromonomer has dissolved to thefullest extent possible, triethylene tetramine (10 g) is added toinitiate curing. The resin is applied immediately after adding thecuring agent, and is fully cured in 24 hours.

EXAMPLE 14 A macromonomer additive for polyamide modification.

The macromonomer of Example 1 (500 g) is blended with polyhexamethyleneadipamide (5 kg) in a laboratory scale extruder to form a concentrate.The concentrate is tumble blended with polyhexamethylene adipamidepellets in a 1 to 5 ratio. The mixed pellets are used to fabricate partsvia injection molding. The resulting molded objects have approximately2% rigid-rod macromonomer incorporated by at least partialtransamidation-transesterification which occurs during blending andmolding.

EXAMPLE 15 Rigid-Rod Macromonomer-reinforced polystyrene.

The macromonomer of Example 6 (12 g) is mixed with styrene (150 g)(freed of inhibitor by distillation under reduced pressure) and benzoylperoxide (3 g) in an evacuable mold. The mold is degassad and sealedunder vacuum. The mold is held at 55°-60° C. for 3 days. The mold iscooled, and opened to release the finished part.

EXAMPLE 16 Rigid-Rod Macromonomer-reinforced fiberglass.

The macromonomer of Example 6 (100 g) is blended with a general purposeunsaturated polyester resin (5 kg) and methyethylketone peroxide (50 g)catalyst and the resulting mixture is applied to glass fiber matting ina mold, using standard hand lay-up techniques. Peak curing temperatureis about 110°-130° C., and curing time is about 30 min.

The above descriptions of exemplary embodiments of macromonomers havingfunctional side groups, the rigid-red polymers, copolymers, and resinsprepared therefrom, and the processes for making same are illustrativeof the present invention. Because of the variations which will beapparent to those skilled in the art, however, the present invention isnot intended to be limited to the particular embodiments describedabove. The scope of the invention is defined in the following claims.

What is claimed is:
 1. A method of producing reinforced polymers, comprising physically blending macromonomers having the structure: ##STR29## wherein each A₁, A₂, A₃, and A₄, on each monomer unit, independently, is C or N; each G₁, G₂, G₃, and G₄, on each monomer unit, independently, is selected from the group consisting of H, solubilizing side groups, reactive side groups, and reactive solubilizing side groups, provided that (1) at least one monomer unit has at least one solubilizing side group and at least one reactive side group, or (2) at least one monomer unit has at least one reactive solubilizing side group, and provided that when any of A₁, A₂, A₃, and A₄ is N, the corresponding G₁, G₂, G₃, or G₄ is nil; the macromonomer has a degree of polymerization, DP_(n), greater than about 6; and adjacent monomer units are oriented head-to-head, head-to-tail, or randomly, with one or more preformed polymers.
 2. A method of producing reinforced polymers comprising:mixing macromonomers having the structure ##STR30## wherein each A₁, A₂, A₃, and A₄, on each monomer unit, independently, is C or N; each G₁, G₂, G₃, and G₄, on each monomer unit, independently, is selected from the group consisting of H, solubilizing side groups, reactive side groups, and reactive solubilizing side groups, provided that (1) at least one monomer unit has at least one solubilizing side group and at least one reactive side group, or (2) at least one monomer unit has at least one reactive solubilizing side group, and provided that when any of A₁, A₂, A₃, and A₄ is N, the corresponding G₁, G₂, G₃, or G₄ is nil; the macromonomer has a degree of polymerization, DP_(n), greater than about 6; and adjacent monomer units are oriented head-to-head, head-to-tail, or randomly, with one or more preformed polymers; and forming chemical bonds between the macromonomers and said one or more preformed polymers, wherein bond formation proceeds in an order selected from the group consisting of bond formation simultaneous with mixing, bond formation subsequent to mixing, and bond formation both simultaneous with and subsequent to mixing of the macromonomers and said one or more preformed polymers.
 3. A method according to claim 2, wherein the mixing process comprises melt blending.
 4. A method according to claim 2, wherein the mixing process comprises solution blending.
 5. A method according to claim 2, wherein the chemical bonds are formed during injection molding.
 6. A method according to claim 2, wherein said one or more preformed polymers is selected from the group consisting of polyamides, polyimides, polyesters, polycarbonates, polyphenylene oxide, polyphenylene sulfide, polyamide-imides, polyamide-esters, polyamide-ethers, po lycarbonate-esters, polyamide-ethers, polystyrene, polyethylene, polypropylene, polyvinylchloride, polyacrylates, polyvinylalcohol, polyvinylacetate, polybutadiene, polydicyclopentadiene, and copolymers thereof.
 7. A method according to claim 2, wherein said one or more preformed polymers is a polyamide and the macromonomers have reactive side groups selected from the group consisting of carboxylic acids, amides, esters, amines, anilines, hydroxyls, and phenols.
 8. A method according to claim 2, wherein said one or more preformed polymers is a polyester and the macromonomers have reactive side groups selected from the group consisting of carboxylic acids, amides, esters, amines, anilines, hydroxyls, and phenols.
 9. A method according to claim 2, wherein said one or more preformed polymers is a polycarbonate and the macromonomers have reactive side groups selected from the group consisting of carboxylic acids, amides, esters, amines, anilines, hydroxyls, and phenols.
 10. A reinforced polymeric material, comprising: ##STR31## wherein each A₁, A₂, A₃, and A₄, on each monomer unit, independently, is C or N; each G₁, G₂, G₃, and G₄, on each monomer unit, independently, is selected from the group consisting of H, solubilizing side groups, reactive side groups, and reactive solubilizing side groups, provided that (1) at least one monomer unit has at least one solubilizing side group and at least one reactive side group, or (2) at least one monomer unit has at least one reactive solubilizing side group, and provided that when any of A₁, A₂, A₃, and A₄ is N, the corresponding G₁, G₂, G₃, or G₄ is nil; the macromonomer has a degree of polymerization, DP_(n), greater than about 6; and adjacent monomer units are oriented head-to-head, head-to-tail, or randomly; andat least one preformed polymer, blended with the macromonomer.
 11. A reinforced polymeric material according to claim 10, wherein the preformed polymer is selected from the group consisting of polyamides, polyimides, polyesters, polycarbonates, polyamide-imides, poly-amide-esters, polyamide-ethers, polycarbonate-esters, and polyamide-ethers. 